Synergistic recovery system and method for carbon source, ammonia nitrogen and pure water

Abstract

The invention provides a carbon source, ammonia nitrogen and pure water collaborative recovery system and method. The system comprises a first-stage immersed breathable membrane unit, a second-stage immersed breathable membrane unit and a pure water recovery unit, the primary immersed breathable membrane unit comprises a stock solution storage tank, and a first expansion membrane tube assembly, a first aeration device and a first temperature controller are arranged in the stock solution storage tank; the secondary immersed breathable membrane unit comprises an acid absorption liquid storage tank; a second expansion membrane tube assembly, a second aeration device and a second temperature controller are arranged in the acid absorption liquid storage tank; the pure water recovery unit comprises a pure water storage tank and a third temperature controller; an inlet and an outlet of the first expansion membrane pipe assembly are communicated with an acid absorption liquid storage tank through a liquid inlet pipe and a liquid outlet pipe, an inlet and an outlet of the second expansion membrane pipe assembly are communicated with a pure water storage tank through a water inlet pipe and a water outlet pipe, and pumps are arranged on the liquid inlet pipe and the water inlet pipe. According to the invention, carbon source concentration, ammonia nitrogen recovery and pure water recovery can be synergistically realized.

Description

Technical Field

[0001] The present invention relates to the technical field of sewage treatment, and in particular to a system and method for the coordinated recovery of a carbon source, ammonia nitrogen and pure water. Background Art

[0002] Wastewater such as landfill leachate, biogas slurry, and waste biomass anaerobic digestion liquid has the characteristics of high ammonia nitrogen, high organic matter, and high water content. It is difficult to effectively treat it with traditional biological, chemical, and physical treatment methods. Gas Permeable Membrane (GPM) technology can be applied to the treatment of high ammonia nitrogen wastewater, including the recovery of ammonia nitrogen from landfill leachate, biogas slurry, and waste biomass anaerobic digestion liquid. The gas permeable membrane technology does not require pressurization and can spontaneously separate gaseous ammonia nitrogen NH3 from the feed solution into the acid absorption solution under the drive of the ammonia nitrogen concentration gradient. The NH3 entering the acid absorption solution will combine with the free protons in the acid absorption solution to form non-volatile NH 4+ , and converted into high-value nitrogen fertilizer.

[0003] However, the permeable membrane technology usually uses alkaline chemicals to adjust the pH value, which is not only easy to cause NH3 to overflow, but also the transmembrane rate of NH3 is low, which greatly reduces the recovery efficiency and increases the operation and subsequent treatment costs; and adjusting the pH value by alkaline chemicals is easy to cause concentration polarization, thereby increasing membrane pollution. In addition, due to the influence of the properties of the permeable membrane, when recovering ammonia nitrogen, water vapor will be transferred to the absorption side along with NH3, resulting in an increase in the volume of the absorption liquid, which reduces the concentration of the recovered ammonia nitrogen product and increases the cost of subsequent treatment.

[0004] In view of this, the present invention is proposed. Summary of the invention

[0005] The purpose of the present invention is to provide a system and method for the coordinated recovery of carbon source, ammonia nitrogen and pure water, which overcomes the problem of increased volume of absorption liquid, improves the recovery efficiency of ammonia nitrogen, and synergistically realizes carbon source concentration, ammonia nitrogen recovery and pure water recovery in the raw liquid.

[0006] The present invention provides a carbon source, ammonia nitrogen and pure water coordinated recovery system, comprising a primary submerged breathable membrane unit, a secondary submerged breathable membrane unit and a pure water recovery unit; wherein the primary submerged breathable membrane unit comprises a stock liquid storage tank, in which a first expansion membrane tube assembly, a first aeration device and a first temperature controller are arranged; the secondary submerged breathable membrane unit comprises an acid absorption liquid storage tank, in which a second expansion membrane tube assembly, a second aeration device and a second temperature controller are arranged; the pure water recovery unit comprises a pure water storage tank and a third temperature controller; the inlet and outlet of the first expansion membrane tube assembly are respectively connected to the acid absorption liquid storage tank through a liquid inlet pipe and a liquid outlet pipe, a liquid inlet pump is arranged on the liquid inlet pipe, and the inlet and outlet of the second expansion membrane tube assembly are respectively connected to the pure water storage tank through a water inlet pipe and a water outlet pipe, a water inlet pump is arranged on the water inlet pipe.

[0007] Specifically, the first temperature controller is provided with a first temperature sensor and a first heating device for heating the raw liquid in the raw liquid storage tank, and the first temperature controller is used to control the temperature of the raw liquid in the raw liquid storage tank at 55-65°C; the second temperature controller is provided with a second temperature sensor and a second heating device for heating the acid absorption liquid in the acid absorption liquid storage tank, and the second temperature controller is used to control the temperature of the acid absorption liquid in the acid absorption liquid storage tank at 45-55°C; the third temperature controller is provided with a third temperature sensor and a refrigeration device for cooling the pure water absorption liquid in the pure water recovery unit, and the third temperature controller is used to control the temperature of the pure water absorption liquid in the pure water storage tank at 15-25°C.

[0008] The first aeration device and the second aeration device are used to aerate the stock liquid storage tank and the acid absorption liquid storage tank, respectively. Specifically, the first aeration device and the second aeration device include an aerator, a flow meter, a releaser and a timer switch, respectively. The aerator is connected to the releaser through an aeration pipe. The releaser of the first aeration device is arranged at the bottom of the stock liquid storage tank, the releaser of the second aeration device is arranged at the bottom of the acid absorption liquid storage tank, the flow meter is arranged on the aeration pipe, and the timer switch is connected to the aerator to control the aeration time. The aeration rates of the first aeration device and the second aeration device are 50-400mL / min / L (i.e., 1L of the liquid to be treated requires 50-400mL of aeration volume per minute), for example, 50-200mL / min / L; the timer switch controls the aeration time interval of the first aeration device and the second aeration device to be 1-6h, for example, 2-6h.

[0009] Furthermore, the first expansion membrane tube assembly and the second expansion membrane tube assembly respectively include expansion membrane tubes, and the material of the expansion membrane tubes is ePTFE, PP or PVDF. Specifically, the first expansion membrane tube assembly and the second expansion membrane tube assembly can be provided with a plurality of expansion membrane tubes, and the plurality of expansion membrane tubes are arranged in parallel, and the inlet ends and outlet ends of the plurality of expansion membrane tubes are respectively fixed by a water collector; the first expansion membrane tube assembly and the second expansion membrane tube assembly are not provided with a shell, and the expansion membrane tubes of the first expansion membrane tube assembly and the second expansion membrane tube assembly are respectively directly exposed to the stock liquid storage tank and the acid absorption liquid storage tank.

[0010] In the system of the present invention, a circulation pipeline for conveying acid absorbent is formed between the expansion membrane tube in the primary submerged breathable membrane unit and the acid absorbent in the acid absorbent storage tank, and a circulation pipeline for conveying pure water is formed between the expansion membrane tube in the secondary submerged breathable membrane unit and the pure water absorbent in the pure water storage tank; when the system is running, the acid absorbent in the acid absorbent storage tank circulates between the acid absorbent storage tank and the expansion membrane tube of the first expansion membrane tube assembly through the liquid inlet pump, and the ammonia nitrogen and water in the stock liquid in the stock liquid storage tank enter the acid absorbent storage tank through the expansion membrane tube of the first expansion membrane tube assembly, the carbon source in the stock liquid is concentrated, and the ammonia nitrogen is removed; at the same time, the pure water absorbent in the pure water storage tank circulates between the pure water storage tank and the expansion membrane tube of the second expansion membrane tube assembly through the water inlet pump, and the water in the acid absorbent in the acid absorbent storage tank enters the pure water storage tank through the expansion membrane tube of the second expansion membrane tube assembly, at this time, the water in the acid absorbent is recovered to the pure water storage tank, and at the same time, the ammonium salt in the acid absorbent is concentrated and recovered.

[0011] Furthermore, the secondary submerged breathable membrane unit is provided with a pH controller, which can be used to monitor whether there is leakage in the acid absorbing liquid and whether concentrated acid needs to be supplemented; it can be understood that the pH controller includes a pH sensor and an acid supplement device, the pH sensor is used to detect the pH value of the acid absorbing liquid, and when the pH of the acid in the acid absorbing liquid is higher than 2, concentrated acid is supplemented to the acid absorbing liquid through the acid supplement device, so that the pH of the acid in the acid absorbing liquid is always maintained below 2.

[0012] The present invention also provides a method for the coordinated recovery of a carbon source, ammonia nitrogen and pure water, which is carried out using the above-mentioned system for the coordinated recovery of a carbon source, ammonia nitrogen and pure water.

[0013] Specifically, the method for synergistically recovering a carbon source, ammonia nitrogen and pure water of the present invention comprises the following steps:

[0014] S1: adding stock liquid to the stock liquid storage tank, adding acid absorption liquid to the acid absorption liquid storage tank, adding pure water absorption liquid to the pure water storage tank, turning on the liquid inlet pump to circulate the acid absorption liquid between the acid absorption liquid storage tank and the first expansion membrane tube assembly, turning on the water inlet pump to circulate the pure water absorption liquid between the pure water storage tank and the second expansion membrane tube assembly;

[0015] S2: The raw liquid storage tank and the acid absorption liquid storage tank are aerated respectively by using the first aeration device and the second aeration device, and the temperatures of the raw liquid, the acid absorption liquid and the pure water absorption liquid are controlled respectively at the same time, so that the ammonia nitrogen and water in the raw liquid enter the acid absorption liquid storage tank through the first expansion membrane tube assembly, and the water in the acid absorption liquid enters the pure water storage tank through the second expansion membrane tube assembly.

[0016] In the present invention, the stock solution is sewage containing high concentration of ammonia nitrogen. It is understood that the stock solution also contains carbon sources such as organic matter. The type of the stock solution is not strictly limited, including but not limited to landfill leachate, biogas slurry, anaerobic digestion liquid of biomass waste, etc. The acid absorption liquid includes at least one of sulfuric acid solution, hydrochloric acid solution, phosphoric acid solution and nitric acid solution, and the concentration of acid in the acid absorption liquid can be 0.05-0.2 mol / L. Pure water absorption liquid can be pure water, reclaimed water, etc.

[0017] The aeration rates of the first aeration device and the second aeration device are 50-400mL / min / L, for example, 50-200mL / min / L, and the aeration time interval is 1-6h, for example, 2-6h. The first aeration device is used to aerate the stock solution storage tank. Aeration can increase the pH value of the stock solution in the stock solution storage tank, increase the concentration of free NH3 in the stock solution, and make it easier for free NH3 to enter the first expansion membrane tube assembly and be absorbed by the acid absorption liquid, which can not only avoid NH3 overflow, but also accelerate the molecular movement to increase the NH3 transmembrane rate, and the ammonia nitrogen recovery efficiency is higher; at the same time, aeration can also reduce concentration polarization, thereby reducing the pollution of the expansion membrane. The second aeration device is used to aerate the acid absorption liquid storage tank. Aeration can reduce the temperature polarization phenomenon, keep the pure water recovery flux of the second expansion membrane tube unaffected, and NH3 immediately reacts to generate NH after entering the acid absorption liquid from the first expansion membrane tube. 4+ The aeration rate and aeration time interval are controlled to be effective in recovering ammonia nitrogen and pure water and reducing the energy consumption of the process.

[0018] In addition, the temperature of the stock solution is controlled to be 55-65°C, for example, 60-65°C. This temperature is conducive to improving the mass transfer flux of ammonia nitrogen, and at the same time, the mass transfer flux of water vapor is also greatly improved, which is conducive to the conversion of ionized ammonia in the stock solution to free ammonia nitrogen and the permeation of free NH3 and water vapor through the expansion membrane tube of the first expansion membrane tube assembly, thereby improving the carbon source concentration multiple and the pure water recovery efficiency; the temperature of the acid absorption liquid is 45-55°C, for example, 55°C, which forms a temperature difference of 10-20°C with the stock solution, which is conducive to improving the water vapor in the stock solution. On the other hand, the operating temperature of 45-55°C is conducive to the water vapor in the acid absorption liquid to pass through the expansion membrane tube of the second expansion membrane tube assembly into the pure water recovery unit, reducing the volume of the acid absorption liquid, increasing the ammonia nitrogen concentration in the acid absorption liquid, and recovering pure water at the same time; the temperature of the pure water absorption liquid is 15-25°C, which forms a certain temperature difference with the temperature of the acid absorption liquid, increasing the transmembrane rate of water vapor and the recovery efficiency of pure water. In addition, the operation at room temperature of 15-25°C can reduce process energy consumption. In particular, the temperature of the stock solution can be controlled to be 10-20°C higher than the temperature of the acid absorption liquid, and the temperature of the acid absorption liquid can be controlled to be 20-40°C higher than the temperature of the pure water absorption liquid. This temperature gradient can maximize the carbon source concentration multiple and the pure water recovery efficiency.

[0019] The carbon source, ammonia nitrogen and pure water coordinated recovery system of the present invention is provided with a primary submerged breathable membrane unit, a secondary submerged breathable membrane unit and a pure water recovery unit, a circulation pipeline for conveying the acid absorption liquid is formed between the acid absorption liquid and the expansion membrane tube of the primary submerged breathable membrane unit, a circulation pipeline for conveying the pure water is formed between the pure water and the expansion membrane tube of the secondary submerged breathable membrane unit, the temperatures of the stock solution, the acid absorption liquid and the pure water absorption liquid are controlled respectively by a first temperature controller, a second temperature controller and a third temperature controller, and at the same time, the first aeration device and the The second aeration device performs aeration, which greatly increases the pH value and free NH3 concentration of the stock solution, so that the free NH3 and water vapor in the stock solution pass through the expansion membrane tube of the first expansion membrane tube assembly into the acid absorption liquid storage tank, thereby increasing the carbon source concentration multiple and the pure water recovery efficiency; at the same time, the water vapor in the acid absorption liquid passes through the expansion membrane tube of the second expansion membrane tube assembly into the pure water storage tank, thereby reducing the volume of the acid absorption liquid and increasing the ammonia nitrogen concentration in the acid absorption liquid, thereby synergistically achieving carbon source concentration, ammonia nitrogen recovery and pure water recovery in the stock solution. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 It is a schematic diagram of the structure of the carbon source, ammonia nitrogen and pure water coordinated recovery system of the present invention.

[0022] Description of reference numerals:

[0023] 1: stock solution storage tank; 2: first expansion membrane tube assembly; 3: first temperature controller; 4: acid absorption liquid storage tank; 5: second expansion membrane tube assembly; 6: second temperature controller; 7: pure water storage tank; 8: third temperature controller; 9: first aerator; 10: first flow meter; 11: first releaser; 12: first timing switch; 13: second aerator; 14: second flow meter; 15: second releaser; 16: second timing switch; 17: pH controller; 18: liquid inlet pump; 19: water inlet pump. DETAILED DESCRIPTION

[0024] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0025] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form also includes the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this description, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0026] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] Example 1

[0028] like Figure 1As shown, the carbon source, ammonia nitrogen and pure water coordinated recovery system of this embodiment includes a primary submerged breathable membrane unit, a secondary submerged breathable membrane unit and a pure water recovery unit; wherein, the primary submerged breathable membrane unit includes a raw liquid storage tank 1, in which a first expansion membrane tube assembly 2, a first aeration device and a first temperature controller 3 are provided; the secondary submerged breathable membrane unit includes an acid absorption liquid storage tank 4, in which a second expansion membrane tube assembly 5, a second aeration device and a second temperature controller 6 are provided; the pure water recovery unit includes a pure water storage tank 7 and a third temperature controller 8; the inlet and outlet of the first expansion membrane tube assembly 2 are connected to the acid absorption liquid storage tank 4 through a liquid inlet pipe and a liquid outlet pipe, respectively, and a liquid inlet pump 18 is provided on the liquid inlet pipe, and the inlet and outlet of the second expansion membrane tube assembly 5 are connected to the pure water storage tank 7 through a water inlet pipe and a water outlet pipe, respectively, and a water inlet pump 19 is provided on the water inlet pipe.

[0029] The primary submerged breathable membrane unit is mainly used to remove ammonia nitrogen from the stock solution and concentrate the carbon source at the same time. The primary submerged breathable membrane unit is provided with a stock solution storage tank 1, which is used to store the stock solution. The stock solution is sewage containing high-concentration ammonia nitrogen and carbon sources such as organic matter, such as landfill leachate, biogas slurry, anaerobic digestion liquid of biomass waste, etc. A first expansion membrane tube assembly 2 is provided in the stock solution storage tank 1. The first expansion membrane tube assembly 2 is provided with a plurality of expansion membrane tubes. The material of the expansion membrane tube is ePTFE, PP or PVDF. The plurality of expansion membrane tubes are arranged in parallel. The inlet and outlet ends of the plurality of expansion membrane tubes are respectively fixed by water collectors. The first expansion membrane tube assembly 2 is not provided with a shell, and the expansion membrane tube is directly exposed in the stock solution storage tank 1. After the stock solution is added to the stock solution storage tank 1, the expansion membrane tube is immersed in the stock solution and is in direct contact with the stock solution, so that the ammonia nitrogen and water in the stock solution pass through the expansion membrane tube and enter the acid absorption liquid storage tank 4 of the secondary submerged breathable membrane unit.

[0030] The first-stage submerged breathable membrane unit is provided with a first aeration device, which is used to aerate the stock solution storage tank 1. Aeration can increase the pH value of the stock solution and increase the concentration of free NH3 in the stock solution, so that the free NH3 can pass through the expansion membrane tube of the first expansion membrane tube assembly 2 and be absorbed by the acid absorption liquid in the expansion membrane tube, thereby avoiding NH3 overflow, accelerating the NH3 transmembrane rate, improving the recovery efficiency of ammonia nitrogen, and reducing the pollution of the expansion membrane tube. Specifically, the first aeration device includes a first aerator 9, a first flowmeter 10, a first releaser 11 and a first timing switch 12. The first aerator 9 is connected to the first releaser 11 through an aeration tube. The first releaser 11 is arranged at the bottom of the stock solution storage tank 1 and is used to release bubbles generated by aeration. The first flowmeter 10 is arranged on the aeration tube. The first timing switch 12 is connected to the first aerator 9 to control the aeration time. The aeration rate of the first aeration device is 50-400 mL / min / L, and the first timing switch 12 controls the aeration time interval of the first aerator 9 to be 1-6 hours.

[0031] The first-stage submerged breathable membrane unit is provided with a first temperature controller 3, which is used to control the temperature of the stock solution in the stock solution storage tank 1 at 55-65°C; specifically, the first temperature controller 3 is provided with a first temperature sensor and a first heating device for heating the stock solution in the stock solution storage tank 1, and the temperature of the stock solution is heated to 55-65°C by the first heating device. Raising the temperature of the stock solution to this temperature is conducive to increasing the mass transfer flux of ammonia nitrogen in the stock solution, and the mass transfer flux of water vapor is also greatly improved, which is conducive to the free NH3 and water vapor in the stock solution to pass through the expansion membrane tube of the first expansion membrane tube assembly 2, thereby improving the carbon source concentration multiple and the pure water recovery efficiency.

[0032] A circulation pipeline for conveying the acid absorption liquid is formed between the primary submerged breathable membrane unit and the acid absorption liquid in the acid absorption liquid storage tank 4. The acid absorption liquid in the acid absorption liquid storage tank 4 circulates between the acid absorption liquid storage tank 4 and the expansion membrane tube of the first expansion membrane tube assembly 2 through the liquid inlet pump 18. By controlling the temperature of the raw liquid and the aeration conditions, the ammonia nitrogen and water in the raw liquid pass through the expansion membrane tube of the first expansion membrane tube assembly 2 and enter the acid absorption liquid storage tank 4, so that the carbon source in the raw liquid is concentrated and the ammonia nitrogen is removed.

[0033] The secondary submerged breathable membrane unit is mainly used to concentrate ammonia nitrogen in the acid absorption liquid. The secondary submerged breathable membrane unit is provided with an acid absorption liquid storage tank 4, which is used to store the acid absorption liquid. The acid absorption liquid can be a sulfuric acid solution, a hydrochloric acid solution, a phosphoric acid solution, a nitric acid solution, etc. The concentration of the acid in the acid absorption liquid can be 0.05-0.2 mol / L. The second expansion membrane tube assembly 5 is provided with a plurality of expansion membrane tubes, the material of the expansion membrane tube is ePTFE, PP or PVDF, and the plurality of expansion membrane tubes are arranged in parallel. The inlet and outlet ends of the plurality of expansion membrane tubes are respectively fixed by a water collector. The second expansion membrane tube assembly 5 is not provided with a shell, and the expansion membrane tube of the second expansion membrane tube assembly 5 is directly exposed to the acid absorption liquid storage tank 4. After the acid absorption liquid is added to the acid absorption liquid storage tank 4, the expansion membrane tube of the second expansion membrane tube assembly 5 is immersed in the acid absorption liquid and in direct contact with the acid absorption liquid, so that the water in the acid absorption liquid passes through the expansion membrane tube and enters the pure water storage tank 7.

[0034] The secondary submerged breathable membrane unit is provided with a second aeration device, which is used to aerate the acid absorption liquid storage tank 4. Aeration can reduce the temperature polarization phenomenon and keep the pure water recovery flux of the second expansion membrane tube unaffected. Specifically, the second aeration device includes a second aerator 13, a second flowmeter 14, a second releaser 15 and a second timing switch 16. The second aerator 13 is connected to the second releaser 15 through an aeration pipe. The second releaser 15 is arranged at the bottom of the acid absorption liquid storage tank 4, which is used to release the bubbles generated by aeration. The second flowmeter 14 is arranged on the aeration pipe. The second timing switch 16 is connected to the second aerator 13 to control the aeration time. The aeration rate of the second aeration device is 50-400mL / min / L, and the second timing switch 16 controls the aeration time interval of the second aerator 13 to be 1-6h.

[0035] The secondary submerged breathable membrane unit is provided with a second temperature controller 6, which is used to control the temperature of the acid absorption liquid in the acid absorption liquid storage tank 4 to 45-55°C; specifically, the second temperature controller 6 is provided with a second temperature sensor and a second heating device for heating the acid absorption liquid in the acid absorption liquid storage tank 4, and the temperature of the acid absorption liquid is heated to 45-55°C by the second heating device. This temperature forms a temperature difference of 10-20°C with the stock solution, which is conducive to improving the mass transfer flux of water vapor in the stock solution; on the other hand, the operating temperature of 45-55°C is conducive to the water vapor in the acid absorption liquid to pass through the expansion membrane tube of the second expansion membrane tube assembly 5 and enter the pure water recovery unit, thereby reducing the volume of the acid absorption liquid, increasing the ammonia nitrogen concentration in the acid absorption liquid, and recovering pure water at the same time.

[0036] The secondary submerged breathable membrane unit is also provided with a pH controller 17 for monitoring whether there is leakage in the acid absorbing liquid and whether concentrated acid needs to be supplemented; specifically, the pH controller 17 includes a pH sensor and an acid supplement device, the pH sensor is used to detect the pH value of the acid absorbing liquid, when the pH of the acid in the acid absorbing liquid is higher than 2, concentrated acid is supplemented into the acid absorbing liquid through the acid supplement device, so that the pH of the acid in the acid absorbing liquid is always lower than 2.

[0037] When the system is running, a circulating pipeline for transporting pure water is formed between the expansion membrane tube in the secondary submerged breathable membrane unit and the pure water absorption liquid in the pure water storage tank 7. The pure water absorption liquid in the pure water storage tank 7 circulates between the pure water storage tank 7 and the expansion membrane tube of the second expansion membrane tube assembly 5. The water in the acid absorption liquid enters the pure water storage tank 7 through the expansion membrane tube of the second expansion membrane tube assembly 5. At this time, the water in the acid absorption liquid is recovered to the pure water storage tank 7, and the ammonium salt in the acid absorption liquid is concentrated and recovered.

[0038] The pure water recovery unit is mainly used to recover and store pure water absorption liquid. The pure water recovery unit is provided with a pure water storage tank 7, which is used to store pure water absorption liquid. The pure water absorption liquid can be pure water, medium water, etc. The pure water recovery unit is provided with a third temperature controller 8, which is used to control the temperature of the pure water absorption liquid in the pure water recovery unit at 15-25°C; specifically, the third temperature controller 8 is provided with a third temperature sensor and a refrigeration device for cooling the pure water absorption liquid in the pure water recovery unit, and the temperature of the pure water absorption liquid is maintained at 15-25°C by the refrigeration device. Maintaining the temperature of the pure water absorption liquid at this temperature is conducive to forming a certain temperature difference with the temperature of the acid absorption liquid, thereby improving the transmembrane rate of water vapor and the recovery efficiency of pure water.

[0039] The above-mentioned carbon source, ammonia nitrogen and pure water coordinated recovery system is used to perform coordinated recovery of carbon source, ammonia nitrogen and pure water, and the steps are as follows:

[0040] S1: Add stock solution to the stock solution storage tank 1, add acid absorption liquid to the acid absorption liquid storage tank 4, add pure water absorption liquid to the pure water storage tank 7, start the water inlet pump 19 to circulate the pure water absorption liquid between the pure water storage tank 7 and the second expansion membrane tube assembly 5, and start the liquid inlet pump 18 to circulate the acid absorption liquid between the acid absorption liquid storage tank 4 and the first expansion membrane tube assembly 2;

[0041] S2: The raw liquid storage tank 1 and the acid absorption liquid storage tank 4 are aerated respectively by using the first aeration device and the second aeration device, and the temperatures of the raw liquid, the acid absorption liquid and the pure water absorption liquid are controlled respectively, so that the ammonia nitrogen and water in the raw liquid enter the acid absorption liquid storage tank 4 through the first expansion membrane tube assembly 2, and the water in the acid absorption liquid enters the pure water storage tank 7 through the second expansion membrane tube assembly 5.

[0042] Specifically, the aeration rates of the first aeration device and the second aeration device are 50-400 mL / min / L, and the aeration time interval is 1-6 hours. In addition, the temperature of the stock solution is controlled to be 55-65°C, the temperature of the acid absorption liquid is controlled to be 45-55°C, and the temperature of the pure water absorption liquid is controlled to be 15-25°C.

[0043] The carbon source, ammonia nitrogen and pure water coordinated recovery system of the present embodiment is provided with a primary submerged breathable membrane unit, a secondary submerged breathable membrane unit and a pure water recovery unit. A circulation pipeline for conveying the acid absorption liquid is formed between the acid absorption liquid and the expansion membrane tube of the primary submerged breathable membrane unit, and a circulation pipeline for conveying the pure water is formed between the pure water and the expansion membrane tube of the secondary submerged breathable membrane unit. The temperatures of the raw liquid, the acid absorption liquid and the pure water absorption liquid are controlled respectively by the first temperature controller 3, the second temperature controller 6 and the third temperature controller 8. At the same time, the first aeration device and the The second aeration device performs aeration, which greatly increases the pH value and free NH3 concentration of the stock solution, so that the free NH3 and water vapor in the stock solution pass through the expansion membrane tube of the first expansion membrane tube assembly 2 into the acid absorption liquid storage tank 4, thereby increasing the carbon source concentration multiple and the pure water recovery efficiency; at the same time, the water vapor in the acid absorption liquid passes through the expansion membrane tube of the second expansion membrane tube assembly 5 into the pure water storage tank 7, thereby reducing the volume of the acid absorption liquid and increasing the ammonia nitrogen concentration in the acid absorption liquid, thereby synergistically achieving carbon source concentration, ammonia nitrogen recovery and pure water recovery in the stock solution.

[0044] Example 2

[0045] This embodiment provides a method for the coordinated recovery of carbon source, ammonia nitrogen and pure water, which is carried out using the system of Example 1.

[0046] Specifically, the raw liquid of this embodiment is landfill leachate, and the ammonia nitrogen concentration is 4000 mg / L; the system operation parameters are as follows: the material of the expansion membrane tube of the first expansion membrane tube assembly is ePTFE, and the material of the expansion membrane tube of the second expansion membrane tube assembly is ePTFE; the acid absorption liquid adopts 1000 mL of 0.05 mol / L sulfuric acid solution, the aeration rate of the first aeration device is 100 mL / min / L, the aeration time interval is 2h, and the temperature of the raw liquid is 60°C; the aeration rate of the second aeration device is 100 mL / min / L, the aeration time interval is 2h, and the temperature of the acid absorption liquid is 55°C; the temperature of the pure water absorption liquid is 25°C.

[0047] After running for 12 hours, the quality parameters of the stock solution were as follows: the ammonia nitrogen concentration was lower than 5 mg / L, the carbon source in the stock solution was concentrated 2.2 times, the ammonium sulfate was concentrated 1.2 times, and 1100 mL of pure water was recovered.

[0048] Example 3

[0049] This embodiment provides a method for the coordinated recovery of carbon source, ammonia nitrogen and pure water, which is carried out using the system of Example 1.

[0050] Specifically, the stock liquid of this embodiment is biogas slurry, and the ammonia nitrogen concentration is 2000 mg / L; the system operation parameters are as follows: the material of the expansion membrane tube of the first expansion membrane tube assembly is PP, and the material of the expansion membrane tube of the second expansion membrane tube assembly is PP; the acid absorption liquid adopts 0.2 mol / L hydrochloric acid solution, the aeration rate of the first aeration device is 200 mL / min / L, the aeration time interval is 4h, and the temperature of the stock liquid is 65°C; the aeration rate of the second aeration device is 200 mL / min / L, the aeration time interval is 4h, and the temperature of the acid absorption liquid is 55°C; the temperature of the pure water absorption liquid is 25°C.

[0051] After running for 12 hours, the quality parameters of the stock solution were as follows: the ammonia nitrogen concentration was lower than 5 mg / L, the carbon source in the stock solution was concentrated 4.4 times, and the ammonium sulfate was concentrated 1.2 times.

[0052] Example 4

[0053] This embodiment provides a method for the coordinated recovery of carbon source, ammonia nitrogen and pure water, which is carried out using the system of Example 1.

[0054] Specifically, the stock liquid of this embodiment is anaerobic digestion liquid of biomass waste, and the ammonia nitrogen concentration is 2000 mg / L; the system operation parameters are as follows: the material of the expansion membrane tube of the first expansion membrane tube assembly is PVDF, and the material of the expansion membrane tube of the second expansion membrane tube assembly is PVDF; the acid absorption liquid adopts 0.1 mol / L nitric acid solution, the aeration rate of the first aeration device is 50 mL / min / L, the aeration time interval is 6h, and the temperature of the stock liquid is 65°C; the aeration rate of the second aeration device is 50 mL / min / L, the aeration time interval is 6h, and the temperature of the acid absorption liquid is 55°C; the temperature of the pure water absorption liquid is 15°C.

[0055] After running for 12 hours, the quality parameters of the stock solution were as follows: the ammonia nitrogen concentration was lower than 5 mg / L, the carbon source in the stock solution was concentrated 4.4 times, and the ammonium sulfate was concentrated 1.8 times.

[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A carbon source, ammonia nitrogen and pure water synergistic recovery system, characterized in that: It includes a primary submerged breathable membrane unit, a secondary submerged breathable membrane unit and a pure water recovery unit; wherein the primary submerged breathable membrane unit includes a stock liquid storage tank, in which a first expansion membrane tube assembly, a first aeration device and a first temperature controller are arranged; the secondary submerged breathable membrane unit includes an acid absorption liquid storage tank, in which a second expansion membrane tube assembly, a second aeration device and a second temperature controller are arranged; the pure water recovery unit includes a pure water storage tank and a third temperature controller; the inlet and outlet of the first expansion membrane tube assembly are connected to the acid absorption liquid storage tank through a liquid inlet pipe and a liquid outlet pipe respectively, and a liquid inlet pump is arranged on the liquid inlet pipe, and the inlet and outlet of the second expansion membrane tube assembly are connected to the pure water storage tank through a water inlet pipe and a water outlet pipe respectively, and a water inlet pump is arranged on the water inlet pipe.

2. The carbon source, ammonia nitrogen and pure water coordinated recovery system according to claim 1, characterized in that: The first temperature controller is provided with a first temperature sensor and a first heating device for heating the raw liquid in the raw liquid storage tank, the second temperature controller is provided with a second temperature sensor and a second heating device for heating the acid absorption liquid in the acid absorption liquid storage tank, and the third temperature controller is provided with a third temperature sensor and a refrigeration device for cooling the pure water absorption liquid in the pure water recovery unit.

3. The carbon source, ammonia nitrogen and pure water coordinated recovery system according to claim 1, characterized in that: The first aeration device and the second aeration device respectively include an aerator, a flowmeter, a releaser and a timing switch. The aerator is connected to the releaser through an aeration pipe. The releaser of the first aeration device is arranged at the bottom of the raw liquid storage tank, and the releaser of the second aeration device is arranged at the bottom of the acid absorption liquid storage tank. The flowmeter is arranged on the aeration pipe, and the timing switch is connected to the aerator to control the aeration time.

4. The carbon source, ammonia nitrogen and pure water coordinated recovery system according to claim 1, characterized in that: The first expansion membrane tube assembly and the second expansion membrane tube assembly respectively include an expansion membrane tube, and the material of the expansion membrane tube is ePTFE, PP or PVDF.

5. The carbon source, ammonia nitrogen and pure water coordinated recovery system according to claim 1, characterized in that: The secondary submerged gas permeable membrane unit is provided with a pH controller.

6. A method for synergistically recovering a carbon source, ammonia nitrogen and pure water, characterized in that: The method is carried out by using the carbon source, ammonia nitrogen and pure water coordinated recovery system described in any one of claims 1 to 5.

7. The method for synergistically recovering carbon source, ammonia nitrogen and pure water according to claim 6, characterized in that: The steps include: S1: adding stock liquid to the stock liquid storage tank, adding acid absorption liquid to the acid absorption liquid storage tank, adding pure water absorption liquid to the pure water storage tank, turning on the liquid inlet pump to circulate the acid absorption liquid between the acid absorption liquid storage tank and the first expansion membrane tube assembly, turning on the water inlet pump to circulate the pure water absorption liquid between the pure water storage tank and the second expansion membrane tube assembly; S2: The raw liquid storage tank and the acid absorption liquid storage tank are aerated respectively by using the first aeration device and the second aeration device, and the temperatures of the raw liquid, the acid absorption liquid and the pure water absorption liquid are controlled respectively at the same time, so that the ammonia nitrogen and water in the raw liquid enter the acid absorption liquid storage tank through the first expansion membrane tube assembly, and the water in the acid absorption liquid enters the pure water storage tank through the second expansion membrane tube assembly.

8. The method for synergistically recovering carbon source, ammonia nitrogen and pure water according to claim 7, characterized in that: The raw liquid includes at least one of landfill leachate, biogas slurry and biomass waste anaerobic digestion liquid; the acid absorption liquid includes at least one of sulfuric acid solution, hydrochloric acid solution, phosphoric acid solution and nitric acid solution; the pure water absorption liquid adopts pure water or reclaimed water.

9. The method for synergistically recovering carbon source, ammonia nitrogen and pure water according to claim 7, characterized in that: The aeration rates of the first aeration device and the second aeration device are 50-400 mL / min / L respectively, and the aeration time interval is 1-6 h.

10. The method for synergistically recovering carbon source, ammonia nitrogen and pure water according to claim 7, characterized in that: The temperature of the stock solution is controlled at 55-65°C, the temperature of the acid absorption liquid is controlled at 45-55°C, and the temperature of the pure water absorption liquid is controlled at 15-25°C.

Images